1. Field of the Invention
The invention relates to security association using authentication and verification of communication devices via public key cryptography in a wireless network.
2. Description of the Related Art
Generally in wireless networks such as Local Area Network (LAN) or Personal Area Network (PAN), devices communicate using secure means such as encrypted data. In a home network, a user may play videos using a DVD player, camcorder, or the like, and transmit the video to a TV via a wireless network. It is possible that the transmitted video may also be played on a TV in a neighbor's home. Another possibility is that a third party within the communication range of the home network may intercept the transmission, alter it, and re-send the altered data to the user's PC. Similarly, a receiving device such as neighbor's PDA makes sure that it receives data only from an intended sender.
To avoid such interruptions and hacking, the transmitted data is usually encrypted and checked so only the intended receiving device can decrypt and validate the data using a predetermined security protocol. To this end, the communicating devices need to share a session key that is not known to other devices. The section key will then be used to secure the user traffic for the current session. The devices use another shared session key for their data communications in the next session to reduce the chance of the session key being compromised or minimize the damage in case the session key is compromised.
To derive a session key, the two communicating devices need to establish a shared master key first. Good security practice does not use the master key to directly encrypt the user application data. Public key (PK) cryptography allows two devices to establish a shared secret, i.e., a shared master key, in broad light—in the presence of eavesdroppers. That is, PK cryptography is not vulnerable to passive attack. Unfortunately, existing techniques of PK cryptography is subject to active attack. An attacker can impersonate itself as one of the intended communication partners and transmit its public key under the disguise of an intended device, thereby tricking the other device to exchange data with the attacker without the device knowing that its communication is being hijacked by an unwanted third party. This is known as man-in-the-middle attack.
Since PK cryptography provides a friendly use model, especially in a wireless environment, there is a need for a method and system for applying PK cryptography to establish a security association, i.e., to establish a shared master key, between two communicating devices without the setback of man-in-the-middle attack.